Process of preparing cellulose nitroacetate



Patented Aug. 18, 1931 UNITED STATES PATENT OFFICE? WILHELIVI WALTER, OF COLOGNE-NIEI-IL, AND LUDVVIG LOCK, DORMAGEN, GER- MANY, ASSIGNORS TO I. G. FARBENINDUSTBIE AKTIENGESELLSQHAFT, F FRANK- FORT-ON-THE-MAIN, GERMANY, A CORPORATION OF GER-MANY PROCESS OF PREPARING GELLULOSE NITRGACETATE N0 Drawing. Application filed July 14, 1930, Serial No. 467,959, and in Germany July 11, 1929.- i

The present invention relates to a process of preparing cellulose nitro acetates.

In the copending application Serial No. 392,257, filed September 12, 1929, there is described a process of preparing cellulose nitro acetate in one operation. The process consists in acetylating the cellulose at temperatures between about 50 and 100 C. by means of acetic acid and acetic anhydride in the presence of .a calculated amount of a salt of nitric acid with a weak inorganic or organic base, such as for example ammonium nitrate, Zinc nitrate, aniline nitrate and urea nitrate, with the addition of .a small amount, 7

say about 0,21% calculated on the amount of the cellulose to be acidylated, of a free mineral acid, especially sulfuric acid. The quantity of the salt of the nitric acid to be added to the reaction mixture depends on the desired nitrogen content of the cellulose nitro acetate to be prepared. Thus, there are obtainable cellulose nitro acetates with a nitrogen content of about 0,1 to 1,8%. But according to this process it has been found easier to produce celullose nitro acetates of a nitrogen content of more than about 0,1% than those of the lower limit of 0,1% stated in the application referred to or even of a still smaller nitrogen content.

In accordance with the present invention cellulose nitro acetates of a nitrogen content of about 0,1% and less down to tracesof nitrogen are obtainable by performing the acetylation process described in application Ser. No. 392,257 with the addition of a small amount of urea, the nitrogen content of the nitro acetyl cellulose thus produced depending on the amount of the urea added in such a manner that with an increasing urea content in the acetylation mixture the nitric acid entering the cellulose molecule is reduced. Generally we add about 0,01 to about 5% of urea calculated on the amount of the cellulose to be acidylated.

The products thus obtained obviously still possess the character of nitro acetates and the properties thereof depending on the respective nitrogen content.

The invention is illustrated by the following examples without being limited thereto, the parts being by weight: ;1 I

Ea'ample 1.1 part of celluloseis heated at C. with 6 parts of acetic anhydride, 4

parts of glacial acetic acid, 0.05 part of ammonium nitrate and 0.005 part of sulfuric acid with the addition-of 0.03 part of urea until a test portion is found to be soluble in chloroform. The nitrogen content is 0.01%. By hydrolysis according to one ofthe known processesthe product can be converted into" a nitro acetate possessing the desired solubility, for example, in acetone. 1 I

Example 2.1 part of ceiluloseis heated at C. with 3, parts of acetic anyhydride, 5 parts of glacial acetic acid, 0.04. part of ammonium nitrate and 0.003 part ofsulfuric acid with the addition of 0.015'part of urea.

until a test portion is found to be soluble in chloroform. The further working up of the primary acetate into a cellulose nitro acetate possess-- ing the desired solubility can be carried out by any of the known methods.

We claim: a

l. The process which comprisesacetylating cellulose at a temperature between about 50 and 100 C. by means of acetic acid anhydride in acetic acid in the presence of asmall amount of a mineral acid and of a salt of nitric acid with a weak base with the addition of a small amount of urea.

2. The process which comprises acetylating cellulose at a temperature betweenabout 50 and 100 G. by means, of'acetic acid an v hydride in acetic acid in the presen e, of a small amount of a mineral aczd and or asalt of nitric acid with a weak base with the addition of about 0.01 to 5% of urea, calculated on the amount of the cellulose.

3. The process which comprises'acetylating cellulose at a temperature between about 50 and 100 C. by means of aceticacid anhydride in acetic acid in the presence of a small amount of sulfuric acid and of a salt of nitric acid with a weak base with the addition of a smallamount of urea.

4;. The process which comprises acetylating cellulose at a temperature between about 50 and 100 C. by means of acetic acid an- The nitrogen content is 0.02%.

hydride in acetic acid in the presence of a temperature of about 85 (1., until a test porsmall amount of sulfuric acid and of a salt tion has become soluble in chloroform.

of nitric acid with a weak base with the ad- In testimony whereof, we aflix our signadition of about 0,01 to 5% of urea, calculated tures.

on the amount of the cellulose.

5. The process which comprises acetylating cellulose at a temperature between about 50 and 100 C. by means of acetic acid anhydride in acetic acid in the presence of 0.21% of sulfuric acid, calculated on the amount of cellulose, and of a salt of nitric acid with a Weak base with the addition of a small amount of urea.

6. The process which comprises acetylating cellulose at a temperature between about 50 and 100 C. by means of acetic acid anhydride in acetic acid in the presence of 0.21% of sulfuric acid, calculated on the amount of cellulose, and of a salt of'nitric acid with a weak base with the addition of about 0,01 to 5% of urea, calculated on the amount of the cellulose.

7 The process which comprises acetylating cellulose at a temperature between about 50 and 100 C. by means of acetic acid anhydride in acetic acid in the presence of a small amount of a mineral acid and of ammonium nitrate with the addition of a small amount of urea.

- 8. The process which comprises acetylating cellulose at a temperature between about 50 and 100 C. by means of acetic acid anhydride in acetic acid in the presence of a small amount of a mineral acid and of ammonium nitrate with the addition of about 0,01 to 5% of urea, calculated on the amount of the cellulose.

9. The process which comprises acetylating cellulose at a temperature between about 50 and 100 C. by means of acetic acid anhydride in acetic acid in the presence of a small amount of sulfuric acid and of ammonium nitrate with the addition of a small amount of urea.

10. The process which comprises acetylating cellulose at a temperature between about 50 and 100 C. by means of acetic a'cidanhydride in acetic acid in the presence of a small amount of sulfuric acid and of ammonium nitrate with the addition of about 0,01 to 5% of urea, calculated on the amount of the cellulose.

11. The process which comprises acetylating cellulose at a temperature between about 50 and 100 C. by means of acetic acid anhydride in acetic acid in the presence of 0.21% of sulfuric acid, calculated on the amount of cellulose, and of ammonium nitrate with the addition of a small amount of urea.

12. The process which comprises heating I 1 part of cellulose with 3 parts of acetic acid anhydride, 5 parts of glacial acetic acid, 0,04 parts of ammonium nitrate, 0,003 parts of sulfuric acid and 0,015 parts of urea at a WILHELM WALTER. LUDWIG LOCK. 

